This invention relates generally to a multifunctional primer for composite building materials, such as fiber cement building materials. In addition, it relates to an improved primer that functions as both a sealer and a primer.
Production of a composite building materials often requires that the surface of the material be modified (e.g., smoother, rougher, textured). For example, building products may be reduced in size by cutting (e.g., by saw or water jet), sanding, punching, shearing. Such modifications may not only change the appearance of the surface, they may also leave the surface burnished and/or with particulates and dust. Unfortunately, such surfaces are very difficult to coat with coating materials (e.g., sealer, primer, paint, stain). This is particularly true for cementitious materials, such as fiber cement. Dusty, burnished and/or smooth fiber cement surfaces are especially problematic and adhesion of a coating to such surfaces is difficult to achieve. In fact, the surface characteristics are often so different after such modifications that there is no adhesion of a first coating material to the building material (e.g., sealer to substrate) and/or no adhesion between a second coating and the first coating (e.g., topcoat to sealer or topcoat to primer).
When a sealer and a primer are desired for a building material, the application of separate coatings can prove complicated and costly. A typical coating process requires multiple heating steps, devices of cleaning, coating, application, heating, drying, curing and packaging, all of which reduce efficiency of work and usage of manpower as well as equipment. There are often compatibility issues between the different coating layers and between the coating and the substrate that must be attended to. In addition, when more than one type of coating is required, durability and performance characteristics of each coating must be properly assessed.